Die



Nov, 16, 1943. H. M. BOLSTON 2,334,379

DIE

Filed July '7, 1943 2 Sheets-Sheet 1 INV ivy-H: w. 4717 Patented Nov. 16, 1943 DIE "Harry M. Bolstbn, Swampscott,Mass,', assignpr it Joseph poration ofiMassachusetts Application July 7, 1943, Serial No. 493591 2 Claims. (01-164-(29') My invention relates :to zdies :rfor Lblanking out shoe Vamps or'other blanks having a ,re-entrant portionfromshe'etmaterial, such as' leather, rubber, fabric or other sheet material.

Dies for this purpose are essentially a :con- .tinuous metal strip shaped :to correspond to the outline of the vamp blank including its reentrant portion and having its edges lying in-spaced parallel planes, one or both of the edges being a continuous cutting edge. Such dies are reenforced by a reenforcing member connecting the inner end of the reentrant portion of the die with one or both of its sides. The reentrant portion of shoe vamps blanked out by such dies must be out very accurately. Consequently, it has been considered essential to reenforce the die by a reenforcing member bridging the throat of the reentrant portion.

Such dies are used in conjunction with a clicking machine having a fiat platform or block which may be constructed of wood, rubber or fibre. The machine also is provided with an arm which can be swung to any position over the platform or block. When the arm is in any such position it can be caused to move toward the platform to strike a hammer-like blow upon a blanking out die positioned below it upon the platform.

In blanking out shoe Vamps or other blanks, a sheet of material, such as leather, is positioned upon the platform of the clicking machine and the die placed upon the sheet material. The arm of the clicking machine is swung to a position over the die and then is caused to strike the die with a hammer-like blow to cause the die to cut a blank from the sheet material.

Considerable trouble has been experienced due to breakage of the reenforcing member bridging the throat of the reentrant portion of the die. I

believe this has been caused by forces created during the cutting operation by the taper of the knife edge acting as a wedge upon the edges of the narrow portion of the sheet material within the reentrant portion of the die tending to spread the throat of the reentrant portion of the die. I have discovered that this trouble can be overcome while maintaining the required cutting accuracy of the die by reenforcing the die so as to permit limited flexibility of the throat region of the reentrant portion. This is accomplished in the die of the invention by reenforcing and tying the inner end of the reentrant portion to the side of the die and eliminating the reenforcing member bridging the throat of the reentrant portion. In addition, in certain dies a reenforcing member is employed bridging the reentrant portion ,at aposition intermediate its throat ;.and inner end .such thatthe portion of the die between the reenforcing memberand the "throat of the reentrant portion may. have aslimited degree :of flexibility. The position of this reenforcing member relative to the throat of :the reentrantportion of the die will vary with the sizejof'the die andparticularly with the width of the reentrant portion. The reenforcingwmember can be positioned closer to the throat pf the reentranti'portion"when, theilatteris wide than it can when the throat is narrow. By reenforcing the die in this manner, the inner end of the reentrant portion, where greatest accuracy in cutting is required, is held relatively rigid while permitting limited flexibility at the throat.

The invention will be more clearly understood from the following description in conjunction with the accompanying drawings, in which;

Fig. 1 is a plan view of a die embodying the invention;

Fig. 2 is a plan view of a die embodying the invention and having a reentrant portion with a wider throat;

Fig. 3 is a perspective view of the platform of a clicking machine, partly in section, with sheet material and the die of the invention thereon, I and Fig. 4 is an elevational view of the die of the invention illustrating its flexibility.

In Fig. 1 a die is illustrated comprising a thin,

narrow and endless strip of metal l0 shaped to correspond to the shape of the edge of a shoe vamp blank. Either or both edges of the strip l0 may be tapered to form a knife edge II. A reenforcing member I5 is secured as by spot welding, at one end to one side of the die l0 and at its other end to the inner end of the reentrant portion 12. A reenforcing member [6 extends between the opposed sections l1 and I8 ,of the reentrant portion l2 and is secured thereto as by spot welding, electric arc welding or riveting so as to connect said sections substantially midway between the ends of the reentrant portion. In certain dies this permits suificient flexibility of the sections l1 and i8 at the throat l9 as well as the faces of the reentrant portion to eliminate the danger of breaking the die during the cutting operation. For example, it is satisfactory in a die having an overall length of about 8%" and an overall width of about 7 with a reentrant portion having a length of about 5%" and a throat of about /2" width. The most desirable location for the reenforcing member [6 relative to the throat l9 will vary in different dies where the shape and size of the die is different and the shape, length and width ,the throat, other conditions being substantially the same. This is illustrated in Fig. 2 where the blanks having a reentrant portion, such as shoe vamps, comprising a continuous metal strip shaped to correspond to the out-line of the blank and having its edges lying in spaced parallel planes, one of said edges being a continuous cutting edge, said die having means for reenforcing its reentrant portion and for tying the inner end thereof to at least one side portion of the die to maintain a fixed relation therebetween without connecting the opposed portions of the reentrant portion at its throat and thereby permit limited flexibility of said portions, said reenforcing means including a reenforcing memdie is substantially the same as that shown in I Fig. 1 except that the throat of the reentrant portion is wider. It will be noted that in the die shown in Fig. 2, the reenforcing member is considerably closer to the throat of the reentrant portion. i 1

Fig. 3 shows the die I0 cutting through a sheet 8' of leather or other suitable material positioned uponthe platform P of a clicking machine. It will be noted that the flexibility of the sections l1 and I8 permits them to be moved in the direction of the' arrows during the cutting operation by the cam action of the taper 25 acting of leather.

I claim:

1. A die for blanking out from sheet material against the edge of narrow strip 26 her connecting said opposed portions at a position intermediatethe inner end and throat of the reentrant portion.

2. A die for blanking out from sheet material blanks having-a reentrant portion, such as shoe vamps, comprising a continuous metal strip shaped to correspond to the outline of the blank and having its edges lying in spaced parallel planes, one ofsaid edges being a continuous cutting edge, and means for reenforcing the reentrant portion of the die while leaving the throat of the reentrant portion unreenforced including a reenforcing member bridging the reentrant portion of the die substantially midway between .the ends thereof.

HARRY M. BOLSTON. 

